1. Field of the Invention
The present invention relates to a text subtitle decoder and a method for decoding text subtitle streams recorded on a recording medium, an example of which is a Blu-ray disc (BD).
2. Discussion of the Related Art
Optical discs are widely used as an optical recording medium for recording mass data. Presently, among a wide range of optical discs, a new high-density digital video disc (hereinafter referred to as “HD-DVD”), such as a Blu-ray Disc (hereafter referred to as “BD”), is under development for writing and storing high definition video and audio data. Currently, global standard technical specifications of the Blu-ray Disc (BD), which is known to be the next generation HD-DVD technology, are under establishment as a next generation optical recording solution that is able to have a data significantly surpassing the conventional DVD, along with many other digital apparatuses.
Accordingly, optical reproducing apparatuses having the Blu-ray Disc (BD) standards applied thereto are also being developed. However, since the Blu-ray Disc (BD) standards are yet to be completed, there have been many difficulties in developing a complete optical reproducing apparatus. Particularly, in order to effectively reproduce the data from the Blu-ray Disc (BD), not only should the main AV data as well as various data required for a user's convenience, such as subtitle information as the supplementary data related to the main AV data, be provided, but also managing information for reproducing the main data and the subtitle data recorded in the optical disc should be systemized and provided.
However, in the present Blu-ray Disc (BD) standards, since the standards of the supplementary data, particularly the subtitle information, are not completely consolidated, there are many restrictions in the full-scale development of a Blu-ray Disc (BD) basis optical reproducing apparatus. And, such restrictions cause problems in providing the supplementary data such as subtitles to the user.